Schlagmann Poroton has developed a double-shell brick chimney that can be installed with a more compact design on a smaller footprint. The development targets the retrofit market, where new exhaust systems are required as part of heating system replacements – such as switching from oil to pellets or gas condensing boilers. Particularly in densely built existing districts and when converting attic spaces, the floor area available for chimneys is often limited. It remains unclear whether the manufacturer provides information on the thermal conductivity or recyclability of the brick components – both relevant criteria in the context of the EU Construction Products Regulation and future EPD requirements for building products.